Replays are supported in Racer. While
racing, press F2 to enter replay mode. A full list of useful keys can be found
here.

Saving a replay can be done while in replay
mode; press S to save. The file is stored in data/replays (as
an .rpl file). These files are relatively small, and you can email them to others.
The person playing back the replay must have the track & car(s) installed
that were used in the replay however.

Also, currently the interpolation of replays is such that some
cameras can give a bit of shake.